Irons existing currently in the market usually comprise a water tank, a steam generating unit and a steam spraying unit. The steam generating unit has an inlet and an outlet, wherein the inlet connected to the inlet-pipe of the water tank, the outlet connected to the steam spraying unit, wherein the steam generating unit used for heating the water to generate steam. The steam spraying unit has plural apertures, and the steam spraying unit is used for spraying steam to iron. Because the steam generating unit has large space, the blast force from the outlet is often inadequate, and a big heating plate must be used to generate enough blast force, increasing cost.